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StructuralHealth Monitoring of Large Concrete Structures · StructuralHealth Monitoring of Large...
Transcript of StructuralHealth Monitoring of Large Concrete Structures · StructuralHealth Monitoring of Large...
Structural Health Monitoringof Large Concrete Structures
Patrik FröjdEngineering Geology, Lund University
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Non‐Destructive Testing (NDT)
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Structural Health Monitoring (SHM)
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Ultrasonic waves
• Velocity• Attenuation• Nonlinearity
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Coda waves
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Continuous waves
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Continuous waves ‐ Lock‐In amplifier
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Signal Recovery 7210 Multi‐channel lock‐in
• ”Locks in” on a referencesignal
• Measures amplitude and phase relative to reference signal
• Samples signals withextremely low SNR
Pulsed vs Continuous waves
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Pulsed vs Continuous waves
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[40 dB = 100x]
dB
dB dB dB
dB dB
dB
Transducer network
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Transducer network
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Transducer network
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Transducer network
13Deviation from baseline (std)
Transducer network
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Deviation from baseline (std)
Deviation from baseline (std)
Conclusions
• Diffuse wave fields suitable for SHM of concrete.• Continuous wave transmission potential for greater distances or higher frequencies at given distance.
• ”Small” damage (~cm) detected over ”long” distance (>8 m).• 50 kHz waves can be used for localization through tomography .
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Thank you!Patrik Frö[email protected]
Hoover Dam – Colorado River, USA16